Subsurface safety valve

ABSTRACT

A combination slip joint and safety valve apparatus including an inner member telescopically and non-rotatably disposed within an outer member, a barrier means for blocking the bore through said members, a normally open flow course extending past said barrier means and adapted to be closed by a longitudinally movable valve sleeve, a means responsive to complete telescoping or closing movement of said members for moving said valve sleeve from open to closed position.

United States Patent 1151 3,653,439 Kisling, Ill 1451 Apr. 1972 54] SUBSURFACE SAFETY VALVE 2,944,607 7/1960 Baker 166/226 I 3,426,847 2/1969 Reardon [72] Invent mm 3,543,849 12/1970 Kilgore ..166/226 [73] Assignee: Schlumberger Technology Corporation,

New York, NY. Primary ExaminerJames A. Leppink AttorneyErnest R. Archambeau, Jr., David L. Moseley, Ed- [22] Flled: June 1970 ward M. Roney, William R. Sherman and Stewart F. Moore [21] Appl. No.: 42,372 [57] ABSTRACT 52] us. c1 ..166 226 A cPmbinatim 1 join safety valve aPParaltus inFludiflg I51] lnt.Cl ..E2lb 33/00 an Inner member telescoplcany and b' dsposed 1 5x1 Fleld 61 Search ..166/224, 226; 251/77, 343 9" member a means bkckmg 9 through said members, a normally open flow course extendmg [56] Rekrences Cited past said barrier means and adapted to be closed by a longituina mova e va ve sleeve, a means res ons1ve to com ete d' lly bl l p pl UNITED STATES PATENTS telescoping or closing movement of said members for moving said valve sleeve from open to closed position. 1,880,778 10/1932 Byers ..166/226 2,917,270 12/1959 Scott ..l66/226 16 Claims, 3 Drawing Figures HT 0 1 2, v 26 l 46 U I g 4 53 V 01 \7 49 55 52 q A 7 45 6 o v, 0 u 67'' a SUBSURIFACE SAFETY VALVE This invention relates generally to downhole valves used in well bores, and more specifically to a new and improved safety valve for use, for example, in testing offshore wells with test equipment suspended from a floating vessel.

Where testing operations such as a drill stem test are conducted from a floating rig subject to vertical oscillations due to wave and tide action, safety is an overriding consideration due to the magnitude of the risk to personnel and equipment should a blow out and fire occur. In a drill stem test, a temporary completion of the well is made to determine the production capability of formations that have been penetrated by the drill bit. A packer is set to isolate the test interval, and a tester valve is opened to enable produced fluid to flow upwardly toward the surface through a pipe string that extends from the tester and the packer to the surface. Pressure recorders record flow and shut-in pressures in a typical manner. The packer is set and the tester is opened and closed by appropriate manipulation of the pipe string.

In order to keep the well under control at all times, various equipment has been developed. For example, a blowout preventer is installed at the sea floor and has rams that can be activated to close off the annulus between the casing and the drill stern. Moreover, valve systems have been developed that are incorporated in the drill stem at the blowout preventer to close off the bore of the drill stem should the pipe be broken off between the sea floor and the floating vessel. However, to applicant's knowledge, a simple and reliable safety valve has not been provided to close off the bore of the drill stem if it is parted at a location below the aforementioned sub-sea equipment. Such an unfortunate circumstance could occur, for example, during a drill stem testing operation where the pipe string or drill stem is being manipulated in order to operate the tester and packer and associated equipment under circumstances where the vessel is heaving vertically while the drill stem is being manipulated.

It is accordingly an object of the present invention to provide a new and improved safety valve that is adapted for incorporation in the drill stern below the floor of the ocean and functions automatically to close off the bore of the drill stern should the stem be broken off at a location below the ocean floor.

Another object of the present invention is to provide a new and improved safety valve structure of the type referred to above that is normally open to enable fluid flow during a drill stem test, but which will automatically close if the drill stem is not in tension, which would occur, for example, if the drill stem were to break in two.

Still another object of the present invention is to provide a new and improved safety valve of the type described, in combination with a balanced slip joint to enable changes in pipe length to occur, for example, due to changes in pressure and temperature in the well, without placing the drill stern in compression so that the safety valve remains open.

A further object of the present invention is to provide a new and improved downhole safety valve that is normally open to permit fluid flow, and which incorporates a vertically movable valve sleeve that is moved to closed position with respect to the flow path by downward movement of a portion of the drill stem which would occur, for example, if the drill stern were to be broken off at a location above the safety valve.

These and other objects are attained in accordance with the concepts of the present invention by a structure that comprises tubular telescoping members coupled together for limited longitudinal movement between extended and contracted positions. A barrier in one of the members blocks the through bore of the members, and a flow course is provided that extends past the barrier for normally providing fluid communication between the respective bores of the members above and below the barrier. A vertically movable valve sleeve is adapted for downward movement to a closed position with respect to the flow course, but is only moved to such closed position in response to complete contraction of the members.

When this occurs, the uppermost member engages the valve sleeve to shift it to closed position. Complete contractive movement will occur should the pipe string break in two above the members because the weight of the broken piece of pipe will force the member to contracted position.

The invention has other objects and advantages that will become more clearly apparent in connection with the following detailed description of the structure and operation of a preferred embodiment, shown in the accompanying drawings in which:

FIG. 1 is a schematic view of an offshore drill stem testing operation being conducted from a floating vessel; and

FIGS. 2A and 2B are longitudinal sectional views, with portion in side elevation, of a combination slip joint and safety valve construction, FIG. 28 forming a lower continuation of FIG. 2A.

Referring initially to FIG. 1, an environment in which the present invention has particular utility is in testing an offshore well 10 that is being drilled from a floating drilling vessel 11. A pipe string 12 is supported in the derrick l3 and extends from the vessel into the well which may be equipped with a sub-sea test tree 14 of the type shown at page 3,730 of the 1969- Composite Catalog of Oilfield Equipment and Services. The pipe string 12 suspends a series of testing tools including a tester assembly 15 coupled to a well packer 16 by a slip joint 17, and a perforated anchor pipe 18 having pressure recorders 19 connected to its lower end. If desired, typical reversing valves 20 and 21 are located at the upper end of the tester assembly 15. The packer 16 is of a known construction shown in U.S. Pat. No. 3,399,729, McGill, dated Sept. 3, 1968 and functions to pack-off and isolate the well zone to be tested. The packer 16, of course, incorporates a typical bypass passage to equalize pressures at the end of the test. The tester assembly 15 is described in detail in application Ser. No. 42,374, Kisling et al., flled concurrently herewith and assigned to the assignee of the present invention. Basically the tester assembly is a valve that is operated by upward and downward motion of the pipe string 12 to alternately flow and shut-in the formations. The lower slip joint 17 and an upper slip joint 17 are also shown in the above-mentioned Kisling et al. application and enable telescoping motion due to wave action and pressure and temperature changes. Moreover, the slip joints are balanced and are unaffected by applied fluid pressures.

A combination slip joint and safety valve assembly 23 in accordance with the present invention is interconnected in the pipe string 12 below the test tree 14 and above the upper slip joint 17. As will be explained in detail below, the assembly 23 also enables changes in length of the pipe 12 due to temperature and pressure changes, and provides a structure for automatically shutting in the pipe string 12 in the event of breakage thereof at a location below the test tree 14.

The safety valve and slip joint assembly 23 is shown in detail in FIGS. 2A and 2B and includes a slip joint section 24 and a safety valve section 25. A mandrel 26 is telescopically disposed within a housing 27 and has a collar 28 that adapts it for connection to the drill pipe 12. The housing 27 has a threaded pin 29 for connection to the drill pipe. The mandrel 26 is sealingly slidable through a suitable seal assembly 30 on the upper end portion of the housing 27, and an enlarged piston section 31 on the mandrel carries seals 32 and 33 that are sealingly slidable on the inner wall surface 34 of the housing. One or more radial ports 35 extend through the wall of the mandrel 26 so that the upwardly facing transverse surfaces of the piston section 31 are subject to the pressure of fluids within the bore 36 of the mandrel, and other ports 37 are provided in the wall of the housing 27 below the piston section 31 to subject the downwardly facing transverse surfaces of the piston section to the pressure of fluids in the well annulus surrounding the housing. The effective pressure area of the piston section 31, which may be considered to be the transverse cross-section area of the annular cavity between the housing 27 and the mandrel 26, is made to be equal to the transverse cross-sectional area circumscribed by the seal assembly 30 at the upper end of the housing for purposes that will be more fully described hereafter.

A seal assembly 39 is fixed to the housing 27 below the ports 37 and at the upper end of a spline sub 40 and seals against the outer surface of the mandrel 26. The spline sub 40 has longitudinally extending splines or ribs 41 that mesh with external splines 42 on a collar 43 on the lower end of the mandrel 26. The splines 41 and 42 function to prevent relative rotation between the mandrel 26 and the housing 27 and to limit the extent of upward movement of the mandrel within the housmg.

The safety valve section of the assembly includes a ported sleeve 45 that is retained between a fixed stop ring 46 and an inwardly extending shoulder 47 on the housing 27. The upper end portion 48 of the sleeve 45 is sealed against the inner wall of the housing 27 by an O-ring 49. A flow path between the sleeve 45 and the housing 27 is provided by the lateral space 50 therebetween, the path extending between grooves 51 at the lower end of the sleeve and several radial ports 52 through the wall of the sleeve below the upper end portion 48. in order to open and close the flow path 50, an annular sleeve valve 53 is fitted within the bore of the sleeve 45, and is slidable between an upper open position where lateral ports 54 register with the sleeve ports 52, and a lower closed position where spaced seals 55 and 56 span the ports 52. The sleeve valve 53 is pressed upwardly in closed position by a coil Spring 57 that rests on an inwardly extending shoulder 58 on the sleeve 45. An upper end surface of the sleeve valve 53 abuts against the stop ring 46 to limit upward movement, and the sleeve valve is sized to extend inwardly of the stop ring for purposes to be described below.

The through-bore of the housing 27 is blocked by a barrier assembly 60 that includes a cylindrical plug 61 having a downwardly facing valve seat 62 and a depending skirt 63 having lateral ports 64. A check ball 65 is pressed upwardly by a spring 66 against the seat 62 to prevent upward flow of fluids through the bore 67 of the plug 61, the spring 66 resting on a retainer plate 68. The plug 61 is sealed with respect to the sleeve valve 53 by an O-ring 69, and with respect to the seal sleeve 45 by an O-ring 70. When the valve sleeve 53 is moved downwardly, one or more bleed ports 71 enable fluid in the cavity below the valve sleeve to pass into the housing bore. The plug 61 is releasably retained in the position shown in the drawings by a shear pin 72.

in operation, the slip joint and safety valve assembly 23 is disposed in the pipe string 12 below the test tree 14. The pipe string 12 is landed or otherwise positioned such that the slip joint section 24 is either in tension and thus extended, or the mandrel 26 can occupy a mid-position with respect to the housing 27 as shown in the drawings. During a drill stem test, the pipe sections above and below the assembly 23 are in communication via the flow passage 50 and the ports 52 and 54. The slip joint section 24 is unaffected by changes in fluid pressures that occur within the pipe string 12 because the transverse area of the piston section 31 is equal to the transverse area of the mandrel 26 at the seal assembly 30. Thus, forces acting upwardly on the mandrel 26 due to greater pressures within the assembly than in the annulus are balanced by equal force acting downwardly on the piston section 31. It will be appreciated, therefore, that the slip joint section 24 can telescope freely to accommodate changes in pipe length due to temperature or pressure changes in the well, and is not influenced by applied fluid pressures. Further, telescoping action of the slip joint section itself does not affect the existing pressures of fluids in the pipe or on the well annulus.

In the event that the pipe string 12 should break in two below the test tree 14, the pipe string will be automatically shut-in as follows. The unsupported piece of broken pipe will fall downwardly, causing the slip joint section 24 to fully contract or close. When this occurs, the lower end section 75 of the collar 43 will engage the valve sleeve 53 and push it downwardly to closed position. The valve sleeve 53 together with the check valve 65 shut off the pipe to upward flow of fluids.

The provision of the upwardly closing check valve 65 enables fluid to be pumped downwardly through the safety valve section 25 with the valve sleeve 53 in closed position, in order to establish circulation and kill the well. in the event that the test tools should become stuck in the well, a drop-bar (not shown) can be dispatched through the pipe string 12 and upon impact cause the pin 72 to shear, thereby releasing the barrier assembly 60. Upon release, the barrier assembly 60 can fall down the pipe string to provide a straight through opening for the passage of a string shot or other device for releasing threaded joints.

It will now be apparent that a new and improved subsurface slip joint and safety valve assembly has been disclosed that will automatically close in the event of pipe breakage to shut-in the well. Since certain changes or modifications may be made by those skilled in the art without departing from the inventive concepts involved, it is the aim of the appended claims to cover all such changes or modifications falling within the true spirit and scope of the present invention.

lCLAlM:

1. Apparatus for use in a well bore, comprising: an inner member telescopically disposed and sealingly slidable within an outer member; means for connecting said members in a pipe string; barrier means for blocking the bore of one of said members; a flow course extending longitudinally of said barrier means interiorly of said one member and between locations in communication with the respective bores of said members above and below said barrier means, the location in communication with the bore of the other of said members being provided by port means extending transversely of said barrier means; sleeve valve means slidable within said barrier means adjacent said port means between spaced longitudinal positions for opening and closing said flow course; and means responsive to telescoping movement of said members for sliding said valve means from open position to closed position.

2. The apparatus of claim 1 further including bias means for normally holding said valve means in open position.

3. The apparatus of claim 1 wherein said barrier means includes a central portion and means for releasably securing said central portion within said one member, release of said securing means enabling removal of said central portion to provide said members with an unobstructed longitudinal opening therethrough.

4. The apparatus of claim 3 further including a flow passage in said central portion, and check valve means for enabling fluid flow in only one direction through said passage.

5. The apparatus of claim 1 wherein said flow course is defined in part by a sleeve member forming a portion of said barrier means and spaced radially with respect to said one member, said port means extending through the wall of said sleeve member, said sleeve valve means being slidable on said sleeve member.

6. The apparatus of claim 5 wherein said sleeve valve means is constituted by an annular member having a ported portion adapted to be aligned in registry with said port means, said annular member having a port closing portion with spaced sealing members adapted to engage said sleeve member above and below said port means.

7. The apparatus of claim 6 further including a spring for normally biasing said sleeve valve means in open position, and stop means for limiting sliding movement of said sleeve valve means in said open position.

8. Apparatus for use in a well bore, comprising: slip joint means including telescoping tubular members coupled together for limited longitudinal relative movement and means for preventing relative rotation of said members; barrier means in one of said members for blocking the throughbore of said members; a flow course extending past said barrier means for providing fluid communication between the respective bores of said members above and below said barrier means; and normally open valve means movably mounted in said barrier means and operatively arranged for opening and closing said flow course, said valve means being closed by a valve actuating portion of the other of said members in response to telescoping movement of said members.

9. The apparatus of claim 8 further including piston and cylinder means on said members for balancing out and cancelling the net effect on said members of changes in fluid pressures within said members.

10. The apparatus of claim 9 wherein said piston means has opposed transverse surfaces exposed respectively to fluid pressures within said members and in the well annulus surrounding said members.

11. The apparatus of claim 8 further including seal means for preventing fluid leakage between said members; and piston means on one of said members sealingly slidable within cylinder means on the other of said members, one face of said piston means being subject to the pressure of fluids within said members and the opposite face of said piston means being subject to the pressure of fluids in the well annulus surrounding said members, the transverse cross-sectional area of said piston means being equal to the transverse area circumscribed by said seal means.

12. Apparatus for use in a well bore comprising: slip joint means including an inner member telescopically disposed within an outer member; said members being movable longitudinally relative to each other between extended and contracted positions; means for preventing relative rotation of said members; piston means on said inner member sealingly slidable within cylinder means on said outer member, the upper face of said piston means being subject to the pressure of fluids within said inner member, the lower face of said piston means being subject to the pressure of fluids in the well annulus surrounding said members; barrier means in said outer member; a flow course extending past said barrier means and providing fluid communication between the respective bores of said members above and below said barrier means; and normally open valve means for closing said flow course, said valve means being closed by movement of said members to contracted position.

13. The apparatus of claim 12 further including seal means for preventing fluid leakage between said members, the transverse cross-sectional area of said piston means being equal to the transverse area circumscribed by said seal means.

14. The apparatus of claim 12 wherein said flow course is defined in part by a sleeve member having radially extending port means, said valve means including a valve sleeve slidable on said sleeve member; spring means for holding said valve sleeve in open position; and means for limiting sliding movement of said valve sleeve in open position.

15. The apparatus of claim 14 wherein said barrier means includes a tubular part having a flow passage and check valve means for preventing fluid flow in an upward direction but enabling fluid flow in a downward direction.

16. The apparatus of claim 15 further including shear means for releasably securing said tubular part in said outer member, release of said shear means enabling removal of said tubular part from said outer member to provide a straight-through vertical path through said members for the passage of wireline instruments or the like. 

1. Apparatus for use in a well bore, comprising: an inner member telescopically disposed and sealingly slidable within an outer member; means for connecting said members in a pipe string; barrier means for blocking the bore of one of said members; a flow course extending longitudinally of said barrier means interiorly of said one member and between locations in communication with the respective bores of said members above and below said barrier means, the location in communication with the bore of the other of said members being provided by port means extending transversely of said barrier means; sleeve valve means slidable within said barrier means adjacent said port means between spaced longitudinal positions for opening and closing said flow course; and means responsive to telescoping movement of said memBers for sliding said valve means from open position to closed position.
 2. The apparatus of claim 1 further including bias means for normally holding said valve means in open position.
 3. The apparatus of claim 1 wherein said barrier means includes a central portion and means for releasably securing said central portion within said one member, release of said securing means enabling removal of said central portion to provide said members with an unobstructed longitudinal opening therethrough.
 4. The apparatus of claim 3 further including a flow passage in said central portion, and check valve means for enabling fluid flow in only one direction through said passage.
 5. The apparatus of claim 1 wherein said flow course is defined in part by a sleeve member forming a portion of said barrier means and spaced radially with respect to said one member, said port means extending through the wall of said sleeve member, said sleeve valve means being slidable on said sleeve member.
 6. The apparatus of claim 5 wherein said sleeve valve means is constituted by an annular member having a ported portion adapted to be aligned in registry with said port means, said annular member having a port closing portion with spaced sealing members adapted to engage said sleeve member above and below said port means.
 7. The apparatus of claim 6 further including a spring for normally biasing said sleeve valve means in open position, and stop means for limiting sliding movement of said sleeve valve means in said open position.
 8. Apparatus for use in a well bore, comprising: slip joint means including telescoping tubular members coupled together for limited longitudinal relative movement and means for preventing relative rotation of said members; barrier means in one of said members for blocking the through-bore of said members; a flow course extending past said barrier means for providing fluid communication between the respective bores of said members above and below said barrier means; and normally open valve means movably mounted in said barrier means and operatively arranged for opening and closing said flow course, said valve means being closed by a valve actuating portion of the other of said members in response to telescoping movement of said members.
 9. The apparatus of claim 8 further including piston and cylinder means on said members for balancing out and cancelling the net effect on said members of changes in fluid pressures within said members.
 10. The apparatus of claim 9 wherein said piston means has opposed transverse surfaces exposed respectively to fluid pressures within said members and in the well annulus surrounding said members.
 11. The apparatus of claim 8 further including seal means for preventing fluid leakage between said members; and piston means on one of said members sealingly slidable within cylinder means on the other of said members, one face of said piston means being subject to the pressure of fluids within said members and the opposite face of said piston means being subject to the pressure of fluids in the well annulus surrounding said members, the transverse cross-sectional area of said piston means being equal to the transverse area circumscribed by said seal means.
 12. Apparatus for use in a well bore comprising: slip joint means including an inner member telescopically disposed within an outer member; said members being movable longitudinally relative to each other between extended and contracted positions; means for preventing relative rotation of said members; piston means on said inner member sealingly slidable within cylinder means on said outer member, the upper face of said piston means being subject to the pressure of fluids within said inner member, the lower face of said piston means being subject to the pressure of fluids in the well annulus surrounding said members; barrier means in said outer member; a flow course extending past said barrier means and providing fluid communication between the respective Bores of said members above and below said barrier means; and normally open valve means for closing said flow course, said valve means being closed by movement of said members to contracted position.
 13. The apparatus of claim 12 further including seal means for preventing fluid leakage between said members, the transverse cross-sectional area of said piston means being equal to the transverse area circumscribed by said seal means.
 14. The apparatus of claim 12 wherein said flow course is defined in part by a sleeve member having radially extending port means, said valve means including a valve sleeve slidable on said sleeve member; spring means for holding said valve sleeve in open position; and means for limiting sliding movement of said valve sleeve in open position.
 15. The apparatus of claim 14 wherein said barrier means includes a tubular part having a flow passage and check valve means for preventing fluid flow in an upward direction but enabling fluid flow in a downward direction.
 16. The apparatus of claim 15 further including shear means for releasably securing said tubular part in said outer member, release of said shear means enabling removal of said tubular part from said outer member to provide a straight-through vertical path through said members for the passage of wireline instruments or the like. 